# NTSB CHI04LA021: Schweizer 269C, N191GC, Ann Arbor, MI, October 26, 2003 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 26, 2003, 14:30 local (19:30 UTC) - Place: Ann Arbor, MI - Coordinates: 42.209167, -83.765556 - Nearby events: https://openairdocs.org/map.md?lat=42.2092&lon=-83.7656&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 2, 2004 - Report: Approved by Office Director - Parties: FAA -- Detroit FSDO - NTSB case key (mKey): 58304 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI04LA021 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58304/pdf - Page: https://openairdocs.org/ntsb/CHI04LA021 ## Probable cause The loss of engine power due to carburetor ice. Weather conditions conducive to the formation of carburetor ice and a roadway were contributing factors. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, climb - to cruise - fuel system,carburetor - ice (cause) - weather condition - carburetor icing conditions (contributing factor) - Forced landing, emergency descent/landing - autorotation - Hard landing, landing - flare/touchdown - terrain condition - roadway/highway ## Analysis The helicopter was substantially damaged during a hard landing following a loss of engine power and subsequent autorotation. The flight instructor reported that shortly after takeoff, within two miles of the departure airport, the helicopter suddenly yawed to the left and the engine began to uncontrollably increase and decrease speed. He noted that it sounded as if the throttle was being rolled on and off. He added that no warning lights were illuminated. The instructor reported that he took control of the heliopter at that time. He stated that he instructed the dual student to apply carburetor heat. However, the engine continued to rev and was "making a popping sound, like it was backfiring." He noted a drop in rotor speed, so he elected to initiate an autorotation. He estimated their altitude was 500 feet above ground level at that point. "The safest spot I could see was a paved road in a subdivision; we struck the ground hard damaging the helicopter," according to the instructor. A post-accident inspection revealed no anomalies. The engine was subsequently removed and torn down. No abnormalities were found during the disassembly and examination. Weather conditions recorded at the departure airport, approximately 20 minutes after the accident, included a temperature of 9 degrees Celcius and dew point of 1 degree Celcius. Data concerning the probability of carburetor icing was obtained from Transport Canada. The conditions bordered regions of serious icing at any power setting and moderate icing at cruise power. ## Factual narrative On October 26, 2003, approximately 1430 eastern standard time, a Schweizer 269C helicopter, N191GC, piloted by a flight instructor and dual student, was substantially damaged during a hard landing following a loss of engine power and subsequent autorotation. The accident occurred approximately two miles southwest of the Ann Arbor Municipal Airport (ARB), Ann Arbor, Michigan. The instructional flight was being operated under the provisions of 14 CFR Part 91 and was not on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The flight instructor and dual student reported no injuries. The local flight departed ARB about 1420. In his written statement, the flight instructor reported that shortly after takeoff, the helicopter suddenly yawed to the left and the engine began to uncontrollably increase and decrease speed. He noted that it sounded as if the throttle was being rolled on and off. He added that no warning lights were illuminated. He stated that he took the control of the helicopter at that time. He stated that he instructed the dual student to apply carburetor heat. However, the engine continued to rev and was "making a popping sound, like it was backfiring." He noted a drop in rotor speed, so he elected to initiate an autorotation. He estimated their altitude at 500 feet above ground level at that point. "The safest spot I could see was a paved road in a subdivision; we struck the ground hard damaging the helicopter," according to the instructor. An individual, who heard the helicopter fly over, reported that it was about 500 feet above ground level, when the engine made three "popping" sounds. He stated the helicopter yawed to the left about 90 degrees and glided down to the pavement. He noted that the engine sounded like it was running fine until the "popping" sounds were heard. A post-accident inspection was conducted. Engine rotation was observed when the starter was engaged at the ignition switch. Fuel was present on-board the aircraft. Its appearance and odor were consistent with 100 low lead aviation fuel. No contamination was observed. Fuel was present at the carburetor inlet and the inlet screen was clean. The magnetos were tested and produced a spark as expected. The engine was removed and torn down. The valve train appeared undamaged and functioned normally. The oil pump was free to rotate and appeared undamaged. The oil filter screen was clean. The bearings and lifter rods appeared to be undamaged and functional. No abnormalities were found. Weather conditions at ARB, recorded at 1453, included a temperature of 9 degrees Celcius and dew point of 1 degree Celcius. Data concerning the probability of carburetor icing was obtained from Transport Canada. The recorded conditions bordered regions of serious icing at any power setting and moderate icing at cruise power. ## Aircraft - Registration: [N191GC](https://openairdocs.org/deregistered/N191GC-2004-03-16), registration cancelled 2004-03-16, S/N 0026, built 1996 (OpenAirDocs) - Reported make and model: Schweizer 269C - Registry model: [Schweizer 269C-1](https://openairdocs.org/model/schweizer-269c-1) (registry code 8059504) (OpenAirDocs) - Registry engine: [Lycoming HO-360 series](https://openairdocs.org/engine/lycoming-ho-360-series) (registry code 41513, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 0026 - Airframe hours: 2238 - Engines: Lycoming HO-360-C1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Bijan Air Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 1, 2003, 38.3 hours before - Departed: ARB, Ann Arbor, MI - Destination: ANN ARBOR, MI - Airport: ARB, Ann Arbor Muni ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 33; injuries: minor; commercial, flight instructor; medical: class 1, valid medical--w/ waivers/lim; last flight review April 14, 2003; seat: left; flight hours: 244 total, 136 in this make and model, 147 as pilot in command, 24 in the last 90 days, 6 in the last 30 days, 0 in the last 24 hours - Student pilot; injuries: minor; student; medical: class 3, valid medical--no waivers/lim.; seat: right ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: 4,700 ft broken - Temperature: 48 °F, dew point 34 °F - Altimeter: 30.01 inHg - Observed at: ARB, 2 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20031026027269A](https://openairdocs.org/incident/20031026027269A), Oct 26, 2003: Hughes 269C1, Ann Arbor, MI, Substantial damage. (-23) At cruise, helicopter veered to left and engine lost power. Tried to regain power unsuccessfully. Performed autorotation and landed. No fire, no… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.